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3/11/2011

A few days ago I wrote about a possible 737 successor, aka 797.
Every day I get a mail with the headlines from ATI (Air Transport Intelligence) and today there where two headlines that catched my eyes.

Boeing sets performance targets for 737 clean-sheet contender (10Mar11
23:29 GMT) Boeing would like its possible 737 clean-sheet design to
have a 15-20% improvement in fuel efficiency over today's
model, VP for marketing Randy Tinseth says at the Asian
Aerospace show in Hong Kong.

Boeing: Twin-aisle 737 replacement could increase aircraft utilisation
(10Mar11 23:25 GMT) Boeing is evaluating how to reduce weight from a 737
replacement with a wider fuselage accommodating two aisles,
vice-president for marketing Randy Tinseth says at the Asian
Aerospace airshow in Hong Kong.

Here are my questions (and in the unlikely case that Randy Tinseth reads this, I would be the most happy man to get the answers directly from himself):

Why does Boeing only target 15-20% better fuel efficiency over the 737? If this is all they want, they can go straight ahead with reengining (Mike Bair said that reengining would yield 11%) plus some (more or less) minor improvements like weight savings through more composites and aerodynamic improvements. As a reengining benefits from grandfather-rights, Boeing would not have to care for some safety regulations that were introduced after the EIS of the 737-100. If Boeing goes with an all-new aircraft, they would have to care for all these with a weight disadvantage for the new aircraft versus the B737NG from the beginning.

Aside from the problems I tried to describe in the earlier entry, I still do not understand how the twin-aisle concept reduces the time for passengers to board and de-board an aircraft. The bottleneck are always the doors, so Boeing should better build wider doors. And for some low-cost airlines they should maybe have an option to build in a same-sized rear exit door, as Ryanair usually does not use airbridges at the terminal but boards and deboards on the tarmac via stairs.